I saw a similar video recently where a swarm of ants starts attacking this much larger insect, and in the shock the insect start giving birth, whereupon the babies are delivered straight into the arms of the swarm and instantly carried off to be devoured.

Notice how weirdly regular the screen shake is? As if, rather than a cell phone in hand, it was done by a drunken cameraman with a tripod? Or the car shadows that sometimes cut off in odd places?

This was a stationary camera that recorded the intersection over time. The person who filmed it then cut the vehicles together to make it look like an amazing feat of driver cooperation, using poorly faked shaky cam to make it more difficult to make out the errors. Thank you Captain D!

Edit: In the spirit of the good captain, I'd like to add: don't let this debunk detract from your enjoyment of the video. It's still a nifty little watch regardless of how it was made, and to me at least is more interesting for having further details to delve into and explore. It's still magical, just a different kind of magic.